Use TrimBrep

[dale (Dale Fugier)]

Just one post, please.

Brep.Trim with flipped Brep as cutter

[image] Trimming relies on the natural surface normal of the surfaces involved. With open surfaces, unless you know exactly which way that points for each object, your trim will always be unpredictable. I suggest you use Split instead and then find a way to test which parts of the surface you want to keep and which you want to discard… –Mitch

– Dale